I have a 2010 Clubman S and want to have better control in turns, -
New 215 45 17's will cost be about 800 installed and NM springs will cost me 800 installed.

Whats the better option?
I currently have 205 45 17's on NON run flats.

Thanks

 

I'm not sure what you mean by "better control" in turns. Better handling in turns maybe?; like a sharper turn-in, greater steering responsiveness, and/or better ultimate grip? What seem to be the main shortcomings of the cornering control you have now?

Maybe you should also add better shocks to the list of options. They're in the same price range, and, from what I've read, the OEM shocks are more of a barrier to good handling than the springs are.

 

changing tire size will not greatly impact handling at least not that small of a change. different tires could give you better grip and feel in the turns. I think in this case the springs would be a better improvement as they will keep the car a bit flatter in the turns. but with lowering springs come other needed upgrades like lower control arms. you can run the stock shocks but will need to replace them in a year or two

 

Swaybar and camber plates.

 

Agree with Sanderskog.

if you are out of alignment this will cause all kinds of handling problems.

Take the pins out of the front and adjust for proper alignment. you may also need to elongate the mounting holes a little to get it to adjust the amount you want. then add camber plates if you really need them.

Better Sway bars would also be a big help it keeping the car stuck to the ground.